Studies to assess the effectiveness of combined recombinant IL-2 and anti-tumor antibodies with and without lymphokine activated killer cells (LAK) in treating metastatic cancer are currently underway. We are involved in protocols assessing these therapies in patients with liver metastases from primary colorectal carcinoma. Computed tomography-guided aspiration biopsy specimens are evaluated by a trained cytotechnologist for adequacy in the radiology suite. The procured specimen is then stained in our laboratory by immunocytochemistry with the antibodies L6 and 17-1A. L6 is a murine monoclonal antibody raised against human lung cancer that stains a carbohydrate antigen present on a variety of adenocarcinomas, including most colon cancers. Only scattered cells in normal tissues appear to react with L6. 17-1A is a murine monoclonal antibody generated against a colorectal cell line. Most colorectal cancers react with 17-1A. Some reactivity for 17-1A has been demonstrated in normal colon. Patients are assigned to a protocol according to their immunocytochemical staining pattern.